In solid‐phase peptide synthesis, the nominal batch size is calculated using the starting resin substitution and the mass of the starting resin. The starting resin substitution constitutes the basis for the calculation of a whole set of important process parameters, such as the number of amino acid derivative equivalents. For Fmoc‐substituted resins, substitution determination is often performed by suspending the Fmoc‐protected starting resin in 20% (v/v) piperidine in DMF to generate the dibenzofulvene–piperidine adduct that is quantified by ultraviolet–visible spectroscopy. The spectrometric measurement is performed at the maximum absorption wavelength of the dibenzofulvene–piperidine adduct, that is, at 301.0 nm. The recorded absorption value, the resin weight and the volume are entered into an equation derived from Lambert–Beer's law, together with the substance‐specific molar absorption coefficient at 301.0 nm, in order to calculate the nominal substitution. To our knowledge, molar absorption coefficients between 7100 l mol−1 cm−1 and 8100 l mol−1 cm−1 have been reported for the dibenzofulvene–piperidine adduct at 301.0 nm. Depending on the applied value, the nominal batch size may differ up to 14%. In this publication, a determination of the molar absorption coefficients at 301.0 and 289.8 nm is reported. Furthermore, proof is given that by measuring the absorption at 289.8 nm the impact of wavelength accuracy is reduced. © 2017 The Authors Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd.

In this paper, laser-ultrasonic techniques are employed to develop a quantitative understanding of the underlying principles of the propagation of guided circumferential waves in two-layered cylindrical components. The high-fidelity, broad-bandwidth, point source/receiver and noncontact nature of these optical techniques are critical elements to the success of this work. The experimental procedure consists of measuring a series of transient, circumferentially propagating waves in a cylindrical waveguide and then operating on these transient waveforms with signal-processing techniques to develop the dispersion relationship for that waveguide; this procedure extracts the steady-state behavior from a series of transient measurements. These dispersion curves are compared to theoretical values. There is good agreement between the experimental and theoretical results, thus demonstrating the accuracy and effectiveness of using laser-ultrasonic techniques to study the propagation of guided circumferential waves.

Es kann gezeigt werden, dass zum einen der Bauschingereffekt beim Werkstoff 54SiCr6 an sich nachgewiesen werden kann und zum anderen die für numerische Simulationen notwendigen Bauschinger-Parameter mit der dargestellten Versuchsmethodik ermittelt werden können. Mit den gewonnenen Werten ist es nun möglich, Werkstoffmodelle für Finite-Element Simulationen entsprechend anzupassen.Aus den Messungen lassen sich sowohl der Tangentenmodul als auch die plastische Rückverformung jeweils in Abhängigkeit von der plastischen Dehnung ableiten. Der Tangentenmodul sinkt mit zunehmender plastischer Verformung -die plastische Rückverformung nimmt mit steigender plastischer Dehnung zu. Der Tangentenmodul hat ab einer gewissen plastischen Dehnung und darüber hinaus ein konstantes Niveau.Schlüsselwörter: Bauschinger Effekt / Tangentenmodul / plastische Rückverformung / Federstahl / Hystereseversuche Simulation of multiple plastic bending deformations processes with loadings vice versa needs suitable parameters. For high-strength spring steel there are not enough investigations available. Investigation and comparison of appropriate parameters for 54SiCr6 will be shown.On the one hand the results of tensile/pressure trials at 54SiCr6 shows that Bauschinger-Effect is existing. Dependence of tangent modulus and plastic reverse deformation to degree of plastic deformation are obvious. Tangent modulus is decreasing according to increasing plastic deformation -plastic reverse deformation increases according to increasing plastic deformation.Investigated parameters probably depend to degree of plastic deformation and do presumable not accord to deformation history.Korrespondenzautor: M. Thomisch,

Zusammenfassung Bei der Schwingungsüberwachung von Wälzlagern ist die Wahl einer geeigneten Sensorposition essentiell. Häufig ist eine lagernahe Anbringung der Sensorik nicht möglich, weswegen eine geeignete Ersatzposition gefunden werden muss. In dieser Arbeit wird ein Ansatz zur Optimierung der Sensorposition vorgestellt, der die Eigenmoden des überwachten Systems mit einbezieht. Als Basis der Untersuchung werden in Trägerkonstruktionen integrierte Wälzlager betrachtet. Es wird aufgezeigt, dass durch die gezielte Positionierung der Sensorik in Bereichen mit hohen Eigenschwingungsamplituden die Signalqualität verbessert werden kann.

In rotating machinery, especially in rolling bearing diagnostics, early and effective fault diagnosis is essential to ensure the reliability of rolling bearings. The commonly used vibration analysis gathers large amounts of information about the dynamics and the general condition of the bearings by recording vibrations generated by a rolling bearing. Within the vibration analysis, the location of the damage can be determined by using envelope demodulation. This is done by identifying the damage frequency within a damaged bearing. Peak-, Root-Mean-Square (RMS)-, and Hilbert-envelopes are the conventional demodulation methods in this field, but each of these methods is different and thus more or less suitable for particular applications. This paper presents a comparative study of these three methods. The selected envelopes are compared and evaluated through experiments, the evaluation of measurement data and the establishment of quality characteristics regarding efficiency and quality. In the process, a decision tool is created to help in the selection of a suitable envelope demodulation technique. A formula for calculating an optimal window size of the Peak-envelope is established, as well as a recommendation for selecting a window size of the RMS-envelope.